Apparatus for the manufacture of fibers, particularly glass fibers



y 1966 M. LEVECQUE ETAL 3,252,777

APPARATUS FOR THE MANUFACTURE OF FIBERS, PARTICULARLY GLASS FIBERS Original Filed July 20, 1960 INVENTORS M4ec5 ZEVECQUE' ATTORNEY United States Patent 3,252,777 APPARATUS FOR THE MANUFACTURE OF FIBERS, PARTICULARLY GLASS FIBERS Marcel Levecqne, Saint-Gratien, and Marcel Mabru, Paris, France, assignors to Compagnie de Saint-Cobain, Nenilly-sur-fieine, Seine, France, a corporation of France Original application July 20, 1960, Ser. No. 44,204, now Patent No. 3,152,878, dated Oct. 13, 1964. Divided and this application Jan. 14, 1964, Ser. No. 337,659 Claims priority, application France, Aug. 7, 1959, 802,313 The portion of the term of the patent subsequent to Oct. 13, 1981, has been disclaimed 11 Claims. (Cl. 6512) This application is a division of our application Serial No. 44,204, filed July 20, 1960, now Patent No 3,152,878.

The present invention relates to .the manufacture of fibers of thermoplastic materials, particularly glass fibers, in which the material in the molten state contained in a hollow rotating body, with orifices on its periphery, is projected through these orifices under the action of centrifugal force.

More especially, it refers to an arrangement of this type, according to which gaseous currents act on the threads of material issuing from the orifices disposed in a plurality of superposed rows, and subject the threads to a drawing-out action to transform them into fibers.

It is the object of the present invention to provide improved mechanisms and devices for the efficient production of these fibers. These improvements serve to impart better mechanical properties to the fibers which are produced and/or appreciable increase in the production of the fibers.

In accordance with the invention, the gaseous current acting on the threads leaving the orifices of the centrifuge body is channeled only over the upper part of the peripheral band. The exterior wall acting to confine the gaseous current extends then only over a part of the height of the peripheral band, for example, between a third and one-half of this height.

The exterior wall may be parallel to the peripheral band of the centrifuge or inclined with respect to it.

The above-mentioned feature of the invention permits considerable increase in the height of the peripheral band of the centrifuge, hence the number of rows of projection orifices for the filaments, and consequently increased production of the apparatus, while obtaining uniform fibers of excellent mechanical quality. Otherwise, that is, if

the annular passage extended over the entire height of the Y peripheral band, only a very small dimension could be given to this height, for the fibers whose numbers increase constantly from top to bottom, would collect in a space too small for their volume and would tend to stick to one outside the wall defining *theann-ular drawing-out gas passage, the gases leaving this ring having the effect of facilitating the evacuation of the fibers and of assuring a complete attenuation thereof.

The invention makes possible the obtention of layers or cushions composed of fine, long fibers, characterized by a high degree of elasticity.

Hereinafter are described, by Way of non-limiting example, several embodiments of the improvements according to the invention.

3,252,777 Patented May 24, 1965 In this description reference is made to the attached drawings wherein:

FIG. 1 is a vertical cross-section of one embodiment of the invention featuring a converging annular passage for the attenuating gases;

FIG. 2 is a vertical cross-section of a second embodiment of the invention featuring an exterior wall which is parallel to the upper part of the peripheral wall of the centrifuge; and

FIG. 3 is a vertical cross-section of a modified embodiment of that shown in FIG. 2, including a blower ring and induction heating for the lower portion of the peripheral wall.

In the embodiment of the invention shown in FIG. 1, the hollow rotating centrifuge body 1 is provided with a cylindrical peripheral wall 2 having a plurality of rows of orifices 3 therein through which the molten material which is fed to the interior of the body is projected in the form of threads.

The gaseous current at high temperature and velocity issues from combustion chamber 4, which is ring-shaped and is disposed above and surrounds the centrifuge. The chamber may be provided with a continuous annular slot 5, concentric with the rotating body, through which the gaseous fluid escapes.

An outer wall 6, placed in the prolongation of the outer lip of slot 5, channels the gaseous current. The height of this outer wall 6 is less than that of the peripheral band, and is in general between one-third and one-half of the height of band 2. The outer wall is inclined with respect to the peripheral band 2 so as to form a converging annular channel for the hot gaseous blast, which has the effect of progressively increasing the speed of the gaseous current from the upper part of the channel-to the outlet thereof. This improves the attenuating action on the fibers issuing from the lower rows of orifices which generally are affected by the lowering in temperature of the gaseous blast adjacent thereto.

In the embodiment shown in FIG. 2, the centrifuge body 1' is provided with a frusto-conical wall 2' having a large number of superposed rows of orifices therein. The annular combustion chamber 4 with the slot 5 therein, is disposed to sweep the hot blast issuing from the latter across the peripheral wall. An outer wall 7, whose height is less than that of the peripheral wall 2', defines the annular passage for the gaseous blast. The wall 7 may be onethird to one-half the height of the wall 2'. This wall 7 may be parallel to the band 2', as shown, or inclined with respect to it,- so as to form, as in the preceding example, a converging passage.

The gaseous blast, on leaving the zone where the wall is placed, presents characteristics of speed and temperatures practically identical with those of the current at the level of outlet lips of annular slot 5. Thus, it is seen that the total height of the band may be increased by a value equal to that of the wall 7, without altering the quality of the fibers, hence making possible an increase in the number of rows of orifices and consequently in the output of the apparatus.

In both of the arrangements shown in FIGS. 1 and 2, it isadvantageous to cool the outer walls 6 and 7, respectively.

FIG. 3 illustrates an arrangement analogous to that of FIG. 2, but which comprises, in addition, a blower ring 8 whose orifice 9 may be continuous and concentric with the rotating body 1. It is desirable to place this ring in such a way that the blower orifices are practically at the level of the lower part of wall 7. The gas jet leaving orifice 9 causes the induction of outer air and acts on the fibers below the rotating .body to facilitate their evacuation.

Also, a winding may be provided which is traversed by a high frequency current for'the induction heating of the lower part of the peripheral band, in order to maintain this band at a suitable temperature.

We claim:

1. An apparatus for manufacturing fibers of thermoplastic material comprising a hollow centrifuge rotatable about a vertical axis and receiving the heated thermoplastic material in the interior thereof, said centrifuge having a peripheral wall of substantial height provided with a plurality of superposed rows of orifices therein for projecting the fibers therethrough by centrifugal force, a combustion chamber surrounding said centrifuge and provided with an annularly-shaped slot for directing an annular hot gaseous blast onto the fibers issuing therefrom in a direction transverse to the planes of emission thereof, an annular channel for said gaseous blast defined on its inner boundary by said peripheral wall and on its outer boundary by an exterior wall having its upper end substantially coinciding with the outer edge of said slot and its lower end terminating adjacent to the upper portion of said peripheral wall.

2. Apparatus as set forth in claim 1 wherein said exterior wall is of hollow construction to permit a cooling medium to pass therethrough.

3. An apparatus as set forth in claim 1 wherein the height of said exterior wall is approximately one-third to one-half the height of the peripheral wall.

4. An apparatus as set forth in claim 1, including an annular blowing chamber surrounding said exterior wall and provided with an annularly-shaped blower slot.

5. An apparatus as set forth in claim 4 wherein said blower slot is disposed at substantially the same level as the lower end of said exterior wall, to effect the induction of outer air at the outlet of said channel and thereby to facilitate the evacuation of the fibers thereat.

6. An apparatus as set forth in claim 5, including an electric induction coil beyond said annular channel and blowing chamber and surrounding the lower part of said peripheral wall to effect a localized heating thereat.

7. An apparatus as set forth in claim 1 including an electric induction coil surrounding the lower part of said peripheral wall to effect a localized heating thereat.

8. An apparatus as set forth in claim 1 wherein the peripheral wall of said centrifuge is of frusto-conical configuration with the number of orifices in the lowermost rows being gerater than those in the upper rows.

9. An apparatus as set forth in claim 1 wherein the annular channel is of substantially uniform cross-sectional area.

10. An apparatus as set forth in claim 1 wherein said annular channel decreases in cross-sectional area from said slot in said combustion chamber to the opposite end thereof.

11. An apparatus as set forth in claim 3 wherein said exterior wall slopes towards said peripheral wall to define an annular channel of convergent cross-section.

References Cited by the Examiner UNITED STATES PATENTS 2,981,974 5/1916 Levecque et al 14 3,077,092 2/1963 Peyches et al 6515 3,084,381 4/1963 Levecque et a1 65-6 3,152,878 10/1964 Levecque et a1. 6514 FOREIGN PATENTS 794,319 4/1958 Great Britain.

DONALL H. SYLVESTER, Primary Examiner. 

1. AN APPARATUS FOR MANUFACTURING FIBERS OF THERMOPLASTIC MATERIAL COMPRISING A HOLLOW CENTRIFUGE ROTATABLE ABOUT A VERTICAL AXIS AND RECEIVING THE HEATED THERMOPLASTIC MATERIAL IN THE INTERIOR THEREOF, SAID CENTRIFUGE HAVING A PERIPHERAL WALL OF SUBSTANTIAL HEIGHT PROVIDED WITH A PLURALITY OF SUPERPOSED ROWS OF ORIFICES THEREIN FOR PROJECTING THE FIBERS THERETHROUGH BY CENTRIFUGAL FORCE, A COMBUSTION CHAMBER SURROUNDING SAID CENTRIFUGE AND PROVIDED WITH AN ANNULARLY-SHAPED SLOT FOR DIRECTING AN ANNULAR HOT GASEOUS BLAST ONTO THE FIBERS ISSUING THEREFROM IN A DIRECTION TRANSVERSE TO THE PLANES OF EMISSION THEREOF, AN ANNULAR CHANNEL FOR SAID GASEOUS BLAST DEFINED ON ITS INNER BOUNDARY BY SAID PERIPHERAL WALL AND ON ITS OUTER BOUNDARY BY AN EXTERIOR WALL HAVING ITS UPPER END SUBSTANTIALLY COINCIDING WITH THE OUTER EDGE OF SAID SLOT AND ITS LOWER END TERMINATING ADJACENT TO THE UPPER PORTION OF SAID PERIPHERAL WALL. 